<?php 
class DateUtil{
	static function firstDayOfMonth($month,$year){
		return date("Y-m-d", mktime(0, 0, 0, $month, 1, $year));
	}
	
	static function lastDayOfMonth($month,$year){
		return date("Y-m-d",mktime(0, 0, 0, $month+1, 0, $year) );
	}
	
	static function extractDay($date){
		return (int)substr ($date,-2);
	}
	
}

?>